System and Method for Rectifying Excessive Clearances of Door Assemblies

ABSTRACT

Systems and methods for rectifying excessive bottom or head clearances of door assemblies are disclosed. An example system may comprise a door sweep installed on a first side of a fire door; a door shoe installed on a second opposite side of the fire door; an intumescent seal in an opening between a bottom edge of the fire door and the door shoe or a floor surface; and end caps installed on two narrow side ends of the fire door.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of U.S. Provisional PatentApplication No. 62/850,848, filed May 21, 2019, and U.S. ProvisionalPatent Application No. 62/878,944, filed Jul. 26, 2019, the contents ofboth are incorporated by reference.

FIELD OF TECHNOLOGY

The present disclosure generally relates to system and method forrectifying excessive clearances of door assemblies, and moreparticularly relates to solutions for bringing fire doors that haveexcessive clearances (gaps) around them into compliance with variousregulatory codes and standards.

BACKGROUND

A fire door is a door with a fire-resistance rating (sometimes referredto as a fire protection rating) used as part of a passive fireprotection system to reduce the spread of fire and smoke betweenseparate compartments of a structure and to enable safe egress from abuilding or structure or ship. Specifically, a fire door by buildingcodes must have appropriate maximum clearances around its perimeter suchthat the fire door functions as desired to stop the flow of fire, hotgases, and smoke in order to minimize the risk and effects of fire andother hazardous situations. However, many fire doors in residential andcommercial buildings, hospitals and schools fail installation andmaintenance inspections due to excessive clearances around them. Firedoors may be rated by time (in minutes or hours) that a door canwithstand exposure to fire test conditions. Typical ratings may include1½ hours (90 minutes), 1-hour (60 minutes), ¾-hour (45 minutes), and⅓-hour (20 minutes), with the maximum rating required of any swingingtype fire door being three hours (180 minutes).

Accordingly, there is a need for providing products and solutions thatare designed and tested to rectify excessive clearances for fire doorsin order to be code compliant.

SUMMARY

In one aspect, the present disclosure provides a system for rectifyingexcessive bottom clearances of door assemblies. The system may comprisea door sweep installed on a first side of a fire door; a door shoeinstalled on a second opposite side of the fire door; an intumescentseal in an opening between a bottom edge of the fire door and the doorshoe or a floor surface; and end caps installed on two narrow side endsof the fire door. The system has been Underwriters Laboratories Inc.(UL) certified for up to 90 minutes for fire doors with bottomclearances up to 1½″. In one embodiment, the door sweep may comprise asolid neoprene rubber seal fitted with a retaining plate. The system mayfurther comprise means for securely fastening at least the door sweep,door shoe, and end caps to the fire door. The intumescent seal may beself-adhesive and made of TECNOFIRE® 2000. The door shoe may comprise anL-shaped door shoe having a vertical portion and a horizontal portion towrap around the bottom edge of the fire door with an opening between thebottom edge of the fire door and a top side of horizontal portion. Theintumescent seal may be positioned on the top side of the horizontalportion of the door shoe. Each of the end caps may cover an openingbetween the bottom edge of the fire door and the horizontal portion ofthe door shoe on either narrow side end of the fire door.

In another aspect, the present disclosure discloses a system forrectifying excessive bottom clearances of door assemblies. The systemmay comprise a door sweep installed on either side of a fire door; anintumescent seal mounted on a bottom edge of the fire door; and end capsinstalled on two narrow side ends of the fire door. The system has beenUL certified for 90 minutes fire doors. The system may further comprisemeans for securely fastening at least the door sweep, door shoe and endcaps to the fire door. The door sweep may include a solid neoprenerubber seal fitted with a retaining plate. The intumescent seal may beself-adhesive and made of TECNOFIRE® 2000. Each of the end cap may coveran opening between the bottom edge of the fire door and a floor surfaceon either narrow side end of the fire door.

In yet another aspect, the present disclosure discloses a method forrectifying excessive bottom clearances of door assemblies. The methodmay comprise: providing a door sweep on a first side of a fire door;mounting a door shoe on a second opposite side of the fire door;providing an intumescent seal in an opening between a bottom edge of thefire door and a floor surface; and mounting end caps on two narrow endsof the fire door. The method may further comprise securely fastening atleast the door sweep, door shoe, and end caps to the fire door. The doorsweep may comprise a solid neoprene rubber seal fitted with a retainingplate. The intumescent seal may be self-adhesive and made of TECNOFIRE®2000. The door shoe may comprise an L-shaped door shoe having a verticalportion and a horizontal portion to wrap around the bottom edge of thefire door with an opening between the bottom edge of the fire door and atop side of horizontal portion. The intumescent seal may be positionedon the top side of the horizontal portion of the door shoe. Each of theend caps covers an opening between the bottom edge of the fire door andthe horizontal portion of the door shoe on either narrow side end of thefire door.

The present disclosure discloses another method for rectifying excessivebottom clearances of door assemblies. The method may comprise: providinga door sweep on either side of a fire door; mounting an intumescent sealon a bottom edge of the fire door; and mounting end caps on two narrowends of the fire door. The method may further comprise securelyfastening at least the door sweep, door shoe and end caps to the firedoor. The door sweep may comprise a solid neoprene rubber seal fittedwith a retaining plate. The intumescent seal may be self-adhesive andmade of TECNOFIRE® 2000. Each of the end cap may cover an openingbetween the bottom edge of the fire door and a floor surface on eithernarrow side end of the fire door.

In accordance with an important aspect, the present disclosure alsoprovides a system for rectifying excessive head clearances of doorassemblies. The system may comprise a door cap straight componentinstalled on a first side of a fire door; a door cap L-shaped componentinstalled on a second opposite side of the fire door; at least oneintumescent strip seal fitted with the door cap L-shaped component; andend caps installed on two narrow ends of the fire door. The system hasbeen UL certified for up to 90 minutes for fire doors with headclearances over ⅛″ and up to ½″. The door cap straight component, thedoor cap L-shaped component, and the end caps may be made of stainlesssteel or steel. The system may further comprise means for securelyfastening at least the door cap straight component, the door capL-shaped component, and the end caps to the fire door. The intumescentstrip seal may be self-adhesive and made of TECNOFIRE® 2000. The doorcap L-shaped component may comprise a vertical portion for mounting ontoan outer surface of the second side of the fire door and a horizontalportion inserted into a gap between a top edge of the fire door and adoor frame above the fire door. The intumescent strip seal may bepositioned on a top side of the horizontal portion. In one embodiment,the intumescent strip seal may comprise a first intumescent strip sealpositioned on a top side of the horizontal portion, and a secondintumescent strip seal positioned on a bottom side of the horizontalportion.

Furthermore, the present disclosure provides a method for rectifyingexcessive head clearances of door assemblies. The method may comprise:mounting a door cap straight component on a first side of a fire door;mounting a door cap L-shaped component on a second opposite side of thefire door; fitting at least one intumescent strip seal with the door capL-shaped component; and mounting end caps on two narrow ends of the firedoor. The method may further comprise securely fastening at least thedoor cap straight component, the door cap L-shaped component, and theend caps to the fire door. The door cap straight component, the door capL-shaped component, and the end caps may be made of stainless steel orsteel. The intumescent strip seal may be self-adhesive and made ofTECNOFIRE® 2000. The door cap L-shaped component may comprise a verticalportion for mounting onto an outer surface of the second side of thefire door and a horizontal portion inserted into a gap between a topedge of the fire door and a door frame above the fire door. Theintumescent strip seal may be positioned on a top side of the horizontalportion. In another embodiment, the intumescent strip seal may comprisea first intumescent strip seal positioned on a top side of thehorizontal portion, and a second intumescent strip seal positioned on abottom side of the horizontal portion.

Additionally, the present disclosure provides a system for rectifyingexcessive head clearances of door assemblies. The system may comprise adoor cap straight component installed on a first side of a fire door; adoor cap L-shaped component installed on a second opposite side of thefire door; and end caps installed on two narrow ends of the fire door.The system has been UL certified for up to 90 minutes for fire doorswith head clearances over ⅛″ and up to ½″. The system may furthercomprise means for securely fastening at least the door cap straightcomponent, the door cap L-shaped component, and the end caps to the firedoor. The door cap straight component, the door cap L-shaped component,and the end caps may be made of stainless steel or steel. The door capL-shaped component may comprise a vertical portion for mounting onto anouter surface of the second side of the fire door and a horizontalportion inserted into a gap between a top edge of the fire door and adoor frame above the fire door.

The present disclosure also provides a method for rectifying excessivehead clearances of door assemblies. The method may comprise: mounting adoor cap straight component on a first side of a fire door; mounting adoor cap L-shaped component on a second opposite side of the fire door;and mounting end caps on two narrow ends of the fire door. The methodmay further comprise securely fastening at least the door cap straightcomponent, the door cap L-shaped component, and the end caps to the firedoor. The door cap straight component, the door cap L-shaped component,and the end caps may be made of stainless steel or steel. The door capL-shaped component may comprise a vertical portion for mounting onto anouter surface of the second side of the fire door and a horizontalportion inserted into a gap between a top edge of the fire door and adoor frame above the fire door.

The above simplified summary of example aspects serves to provide abasic understanding of the present disclosure. This summary is not anextensive overview of all contemplated aspects, and is intended toneither identify key or critical elements of all aspects nor delineatethe scope of any or all aspects of the present disclosure. Its solepurpose is to present one or more aspects in a simplified form as aprelude to the more detailed description of the disclosure that follows.To the accomplishment of the foregoing, the one or more aspects of thepresent disclosure include the features described and exemplary pointedout in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated into and constitute apart of this specification, illustrate one or more example aspects ofthe present disclosure and, together with the detailed description,serve to explain their principles and implementations.

FIG. 1 illustrates a first embodiment of a UL certified intumescent doorbottom system for fire doors with excessive door bottom clearances up to1½″, according to an exemplary aspect;

FIG. 2A shows an exploded view of the first embodiment, according to anexemplary aspect;

FIG. 2B shows a first end view of the first embodiment with end capsremoved, according to an exemplary aspect;

FIG. 2C shows an assembled view of the first embodiment, according to anexemplary aspect;

FIG. 2D shows a second end view of the first embodiment, according to anexemplary aspect;

FIG. 3 illustrates a first example door sweep of the first embodiment,according to an exemplary aspect;

FIG. 4 illustrates a second example door sweep of the first embodiment,according to an exemplary aspect;

FIG. 5 illustrates a first example L-shaped door bottom shoe of thefirst embodiment, according to an exemplary aspect;

FIG. 6 illustrates a second example L-shaped door bottom shoe of thefirst embodiment, according to an exemplary aspect;

FIG. 7 illustrates an example stainless steel end cap of the firstembodiment, according to an exemplary aspect;

FIG. 8 illustrates a second embodiment of an UL certified intumescentdoor bottom system for fire doors with excessive door bottom clearancesup to 1½″, according to an exemplary aspect;

FIG. 9 illustrates an example door sweep of the second embodiment,according to an exemplary aspect;

FIG. 10A illustrates a first embodiment of a door head system for firedoors with excessive door head clearances over ⅛″, according to anexemplary aspect;

FIG. 10B illustrates a detailed view of a top corner of a fire door ofthe first embodiment, according to an exemplary aspect;

FIG. 11A illustrates a second embodiment of the door head system forfire doors with excessive door head clearances up to ½″, according to anexemplary aspect;

FIG. 11B illustrates a detailed view of a top corner of a fire door ofthe second embodiment, according to an exemplary aspect;

FIG. 12 illustrates an example door cap straight component of a doorhead system, according to an exemplary aspect;

FIG. 13 illustrates an example door cap L-shaped component of a doorhead system, according to an exemplary aspect; and

FIG. 14 illustrates an example door end cap of a door head system,according to an exemplary aspect.

DETAILED DESCRIPTION

Various aspects of the present disclosure will be described withreference to the drawings, wherein like reference numerals are used torefer to like elements throughout. In the following description, forpurposes of explanation, numerous specific details are set forth inorder to promote a thorough understanding of one or more aspects of theinvention. It may be evident in some or all instances, however, that anyaspects described below can be practiced without adopting the specificdesign details described below.

The present disclosure generally relates to solutions and systems forbringing fire doors that have excessive clearances (gaps) intocompliance with various regulatory codes and standards. For example,perimeter gaps in doors may refer to the distance between the side edgeof a door and door frame as measured on a pull side of the opening. Doorbottom clearances or door bottom gaps may refer to the distance betweenthe bottom of the door and the floor or a door threshold (a structure(e.g., a strip or wood or metal) that runs across the bottom of a doorframe). Door head clearances or door head gaps may refer to the distancebetween the top edge of the door and an adjacent structure (e.g., a doorframe edge immediately above the door). Proper gap tolerances may ensurethat a fire door will perform as it is intended. Gaps or clearances thatare outside of tolerance may lead to compromised fire door integrity inhazardous situations as well as not allowing the fire door latchingmechanism to engage fully as it is required to do so by relevant codesor regulations. National fire protection association (NFPA), one codestandard for fire doors, requires that fire doors must be inspected onan annual basis. For example, maximum allowable perimeter gap is ⅛″ forwood doors, ⅛″+/− 1/16″ for metal doors. Maximum allowable door bottomgap is ¾″. Gaps that exceed these maximum allowable tolerances mayresult in a non-compliant fire door that needs to be repaired orreplaced entirely.

Standard test methods for fire door assemblies, such as UL 10C, UL 10B,NFPA 80 or NFPA 252, measure the ability of door assemblies of variousmaterials and types of construction for use in wall openings during afire to retard the passage of the fire and evaluate the fire-resistantproperties of these door assemblies. These tests may expose a specimen(e.g., a test door assembly) to a standard fire exposure controlled toachieve specified temperatures throughout a specified time period,followed by the application of a specified standard fire hose stream.The exposure, however, is not representative of all fire conditions,which vary with changes in the amount, nature, and distribution of fireloading, ventilation, compartment size and configuration, and heat sinkcharacteristics of the compartment. It does, however, provide a relativemeasure of fire performance of door assemblies under these specifiedfire exposure conditions. In conducting such tests, for example, a doormay be mounted in an opening of a fire proof wall, and one side of thedoor is exposed to a predetermined range of temperatures over apredetermined period of time, followed by the application of ahigh-pressure hose stream that causes the door to erode and provides athermal shock to the assembly. Doors are given a fire rating based onthe duration of the heat exposure of 20 minutes, 30 minutes, 45 minutes,one hour (60 minutes), 1½ hours (90 minutes) or three hours (180minutes). The door assembly may receive the fire rating when it remainsin the wall opening for the duration of the fire test and hose stream,within certain limitations of movement and without developing openingsthrough the door either at the core or around the edge material.

According to aspects of the present disclosure, a UL certified solutionor intumescent door bottom system for fire doors with excessive doorbottom clearances up to 1½″ may comprise a door sweep on a first side ofa door assembly, a door shoe with an intumescent strip seal on a secondopposite side of the door assembly, end caps to cover both side ends ofthe door assembly, and means for securely fastening or fixing the doorsweep, door shoe, end caps and other components to the door assembly.The disclosed system may be installed at the bottom of a fire door torectify excessive door bottom gaps and create a barrier against, e.g.,sound, light, fire, smoke and air infiltration in hazardous situations.The disclosed system may also be configured to prevent water seepage,dust and moisture from coming through the gap under the fire door.

Referring to FIGS. 1 and 2A-2D, in one embodiment of the presentdisclosure, system 100 may comprise a brushed stainless steel or steelretaining plate with a neoprene rubber sweep 104 on e.g., a pull side ofa fire door 102 that may be a wood or metal fire door, a brushedstainless steel or steel door shoe 106 with an intumescent strip seal110 on e.g., a push side of the fire door 102, brushed stainless steelor steel end caps 108 on both narrow side ends of the fire door 102, anda number of sheet metal screws 112 or any other suitable means forfastening all of the above-mentioned component pieces to the bottom offire door 102. For purposes of explanation, a door assembly generallyhas a push side and a pull side. A push side may refer to the side wherethe door swings away from a user and the user may push the door to open,and the pull side refers to the side where the door swings toward theuser and the user may pull the door to open. It should be appreciatedthat the installation of door sweep 104 and door shoe 106 on pull and/orpush sides of fire door 102 may depend upon e.g., specific configurationand dimension of fire door 102. Further, other materials may be used inplace of neoprene rubber as a sweep material. Some commonly used sweepmaterials may include but not limited to: silicone rubber, ethylenepropylene diene monomer (EPDM) rubber, vinyl and other thermoplastics,nylon Brush, and polyurethane. System 100 may be used on up to 90minutes UL 10B and UL 10C wood or hollow metal fire doors with bottomclearance exceeding ¾″ up to 1½″. System 100 is UL certified for 90minutes fire doors with bottom clearance up to 1½″.

Pull side door sweep 104 may have different lengths, such as 36″ and 48″as illustrated in FIGS. 3 and 4, respectively, to accommodate fire doorshaving different widths. In one embodiment, pull side door sweep 104 maycomprise a solid neoprene rubber seal (e.g., ⅛″ in thickness) fittedwith (e.g., via adhesive tapes, glue or any suitable adhesion means) astainless steel or steel retaining plate having an angled edge (e.g.,150° between the edge and main body of the plate) and a wall thicknessof 0.036″. This angled edge of the retaining plate may help achieve afinished look of door sweep 104 on fire door 102 and prevent dust fromaccumulating on the neoprene rubber seal over time. A plurality ofthrough holes may be provided along an upper edge of stainless steel orsteel retaining plate (e.g., ⅜″ to the upper edge) such that door sweep104 may be securely fastened near the bottom side of door 102 on thepull side. Door sweep 104 helps protect the intumescent strip seal 110during a fire which may expand to seal the space between the bottom edgeof door 102 and door shoe 106.

Referring now to FIGS. 5 and 6, push side door shoe may be a stainlesssteel or steel L-shaped door shoe 106 having a vertical portion 114 tofasten near the bottom of the door 102 and a horizontal portion 116 towrap around the bottom edge of door 102 on the push side. In accordancewith aspects of the present disclosure, as shown in FIGS. 1 and 2B, doorshoe 106 may be so positioned on door 102, such that there is an openingbetween the bottom edge of door 102 and a top side of horizontal portion116 under door 102. A bottom side of horizontal portion 116 may bepositioned at most ¾″ above the floor surface. It should be appreciatedthat the clearance between the horizontal portion 116 of door shoe 106and floor surface or door threshold may be determined and selected inaccordance with the allowable door bottom gap required by relevant firedoor regulations and codes (e.g., at most ¾″). Door shoe 106 may havedifferent lengths, such as 36″ and 48″ illustrated respectively in FIGS.5 and 6, to accommodate fire doors having different widths. In oneembodiment, the vertical portion 114 may have a height of 2″ and a wallthickness of 0.036″. A plurality of through holes may be provided alongan upper edge of vertical portion 114 (e.g., ⅜″ to the upper edge), suchthat door shoe 106 may be securely fastened near the bottom side of door102 and substantially flush with the outer surface of door 102 on thepush side. The number, exact positioning, arrangement and spacing ofthese through holes may depend upon the dimension of the door 102 anddesired mechanical strength and stability of door shoe 106. Horizontalportion 116, which may have a width of 1¾″ and may be substantiallyperpendicular to the vertical portion 114, is configured to hold anintumescent strip seal 110 in place under door 102 during a fire. In oneembodiment, intumescent strip seal 110 may be a 1.3 mm thickself-adhesive intumescent seal made of TECNOFIRE® 2000 or any suitablefire protection material mounted on the top side of horizontal portion116 of door shoe 106. It should be appreciated that the specificthickness and/or width of the intumescent seal 110 may be selected inconnection with characteristics of the intumescent materials used suchas expansion ratio, char porosity and thermal conductivity coefficient.When exposed to high heat of a fire, the intumescent strip seal 110 mayexpand to fill the opening between the bottom edge of door 102 and thetop side of horizontal portion 116, thereby insulating the bottom of thedoor 102 and protecting it from deteriorating and failing during thefire. The width of horizontal portion 116 may depend on the width of theintumescent strip seal 110 and door 102. Preferably, the horizontalportion 116 is wide enough to hold the intumescent strip seal 110 andspan most of the bottom edge of door 102.

Furthermore, as shown in FIGS. 1, 2A, 2C, 2D and 7, stainless steel orsteel end caps 108 may be installed on both side ends of door 102 viascrews 112 or any other suitable means. End caps 108 may substantiallycover the opening under the bottom edge of door 102 down to the top sideof horizontal portion 116 of door shoe 106, thereby containing theintumescent strip 110 during a fire and allowing it to stay under thedoor 102. End caps 108 may have a width slightly narrower than that ofthe door thickness, such that they do not extend beyond the edges ofdoor 102 and are easy to install. In one embodiment, as illustrated inFIG. 7, stainless steel end caps 108 may be rectangular in shape andhave a wall thickness of 0.036″. It should be appreciated that the exactshape, dimensions, and positioning of end caps 108 may vary dependingupon specific configuration and installation of door shoe 106 on door102. For example, end caps 108 may be L-shaped wrapping around thenarrow end of door 102 with a vertical portion flush with door surfaceand a horizontal portion under the door frame.

To install system 100 on a fire door assembly to rectify excessive doorbottom clearances, one may first measure and determine the dimensionsand location of L-shaped stainless steel door shoe 106 with anintumescent strip seal 110 in relation to the bottom edge of door 102 onthe push side. Thereafter, one may close door 102 and hold door shoe 106at the bottom of push side of door 102 with approximately ⅜″ (at most¾″) clearance above sill or floor surface. It should be appreciated thatthe clearance between the horizontal portion 116 of door shoe 106 andfloor surface may be determined and selected in accordance with theallowable door bottom gap required by relevant fire door regulations andcodes (e.g., at most ¾″). Via the plurality of through holes providednear the upper edge of vertical portion 114 as illustrated in FIGS. 5and 6, one may mark screw holes on the bottom push side of door 102 andthen drill pilot holes for screws using e.g., a 7/64″ drill bit.Subsequently, door shoe 106 may be installed on the bottom of push sideof door 102 with screws or other fastening means and its position may befurther adjusted to e.g., ⅜″ (at most ¾″) clearance above sill/thresholdor floor.

Next, to install door sweep 104 on the pull side of door 102, one mayalso first measure and determine the dimension and location of doorsweep 104 in relation to the bottom edge of door 102. For example, thestainless steel or steel retaining plate may be 2″ in height with itsbottom edge ¼″ higher than that of the neoprene rubber seal.Subsequently, one may close door 102, hold door sweep 104 at a selectedposition near the bottom of door 102, and tap down until contact is madebetween door sweep 104 and threshold. Via a plurality of through holesprovided near the upper edge of stainless steel retaining plate asillustrated in FIG. 2A, one may mark screw holes on the bottom of thepull side of door 102 and then drill pilot holes for screws using e.g.,a 7/64″ drill bit. Subsequently, door sweep 104 may be installed on thebottom of pull side of door 102 with screws provided, and its positionmay be further adjusted so as not to impede proper closing and latchingof door 102. Thereafter, as shown in FIGS. 2A, 2C and 2D, end caps 108may be installed on both narrow side ends of door 102. One skilled inthe art should appreciate that various means may be used for securelyfastening the door sweep, door shoe, end caps and other components tofire door 102.

In another embodiment of the present disclosure, referring to FIGS. 8and 9, system 200 may comprise a brushed stainless steel or steelretaining plate with a neoprene rubber sweep 204 on each side of a firedoor 202 that may be a wood or metal fire door, an intumescent stripseal 206 mounted directly on the bottom edge of door 202, brushedstainless steel or steel end caps 208 on both narrow side ends of thedoor 202, and a number of sheet metal screws 210 or any other suitablemeans for fastening all of the above-mentioned component pieces to thebottom of door 202. System 200 may be used on up to 90 minutes UL 10Band UL 10C wood or hollow metal fire doors with bottom clearanceexceeding ¾″ up to 1½″.

As shown in FIGS. 8 and 9, each door sweep 204 may comprise a solidneoprene rubber seal (e.g., ⅛″ in thickness) fitted with a stainlesssteel or steel retaining plate having an angled edge (e.g., 150° betweenthe edge and main body of the plate) and a wall thickness of 0.036″.This angled edge of the retaining plate may help achieve a finished lookof door sweep 104 on fire door 102 and prevent dust from accumulating onthe neoprene rubber seal. Door sweep 204 may be configured to helpcontain the intumescent strip seal 206 during a fire which expands toseal the door 202 to the floor, thereby providing a barrier against,e.g., sound, light, fire, smoke and air infiltration in hazardoussituations. Door sweep 204 may also be configured to prevent waterseepage, dust and moisture from coming through the gap under the firedoor from both sides. Intumescent strip seal 206 may be a 2.6 mm thickself-adhesive intumescent seal made of TECNOFIRE® 2000 or any suitablefire protection materials mounted on the bottom edge of door 202. Itshould be appreciated that the specific thickness and/or width of theintumescent seal may be selected in connection with characteristics ofthe intumescent materials used such as expansion ratio, char porosityand thermal conductivity coefficient. When exposed to high heat of afire, the intumescent strip seal 206 may expand to fill the openingbetween the bottom edge of door 202 and floor surface, therebyinsulating the bottom of the door 202 and protecting it fromdeteriorating and failing during the fire.

Furthermore, stainless steel or steel end caps 208 may be installed onboth narrow side ends of door 202 via screws 210 or any other suitablemeans to substantially cover the opening under the bottom edge of door202 down to the floor surface in order to contain the intumescent strip206 during a fire and allow it to stay under the door 202.

To install system 200 on a fire door assembly to rectify excessive doorbottom clearances, one may first clean the bottom edge of door 202 withe.g., clean wipe to remove dust, oil, grease and dirt. High glosspainted surfaces may require roughening with a scotch brite pad or sandpaper so adhesive will bond properly. Thereafter, one may measure anddetermine the dimensions of intumescent strip seal 206 to fit the doorwidth. After removing the protective backing, one may positionintumescent strip seal 206 on the door bottom edge and adhere seal bypressing firmly (e.g., 15 lbs. of pressure required) along entire lengthof the door bottom edge.

Next, to install door sweep 204 on each side of door 202, one may alsofirst measure and determine the dimension and location of door sweep 104in relation to the bottom edge of door 202. For example, the stainlesssteel retaining plate may be 2″ in height with its bottom edge ¼″ higherthan that of the neoprene rubber seal. Subsequently, one may close door202, hold door sweep 204 at a selected position near the bottom of door202, and tap down until contact is made between door sweep 204 andthreshold or floor. Via a plurality of through holes provided near theupper edge of stainless steel retaining plate as illustrated in FIG. 9,one may mark screw holes on the bottom of door 202 and then drill pilotholes for screws using e.g., a 7/64″ drill bit. Subsequently, door sweep204 may be installed on the bottom of door 202 on both sides with screwsprovided, and its position may be further adjusted so as not to impedeproper closing and latching of door 202. Thereafter, as shown in FIG. 8,stainless steel or steel end caps 208 may be installed on both narrowside ends of door 202.

Moreover, the present disclosure discloses a door head solution orsystem for rectifying excessive door head clearances (e.g., over ⅛″ upto ½″) of a fire door. As will be described below, such a system may beinstalled at a head portion of the fire door to create a barrieragainst, e.g., sound, light, fire, smoke and air infiltration inhazardous situations and allow the fire door to pass a 90 minutepositive pressure fire endurance and hose stream test.

FIGS. 10A and 10B illustrate a door head system 300 for fire doors withexcessive door head clearances over ⅛″ (maximum clearance of ⅛″ ispermitted by NFPA 80), according to aspects of the present disclosure.System 300 may comprise a brushed stainless steel or steel door capstraight component 302 (shown in FIG. 12) mounted on a first side (e.g.,pull side) of a fire door 102 that may be a wood or metal fire door, anda brushed stainless steel or steel door cap L-shaped component 304(shown in FIG. 13) mounted on a second side (e.g., push side) of firedoor 102 and fitted with an intumescent seal 306. System 300 mayadditionally comprise end caps 308 mounted on both side ends of firedoor 102 to protect the intumescent seal 306 and the integrity of thehead portion of door 102 in hazardous situations. A number of sheetmetal screws or any other suitable means may be additionally provided bysystem 300 for fastening all of the above-mentioned component pieces tothe head portion of fire door 102. It should be appreciated that theinstallation of door cap straight component 302 and L-shaped component304 on pull and/or push sides of fire door 102 may depend upon, amongstother things, specific configuration and dimension of fire door 102.

Door cap straight component 302 may have different widths (e.g., 1¼″)and lengths (e.g., 36″ and 48″) to accommodate fire doors havingdifferent dimensions. In one embodiment, referring to FIG. 12, door capstraight component 302 may have a uniform thickness (e.g., 0.036″)selected to allow it to be securely fastened onto the surface of door102 on the pull side via a plurality of through holes without affectingthe movement of door 102. The number, exact positioning, arrangement andspacing of these through holes may depend upon the dimension of door 102and desired mechanical strength and stability of component 302. Torectify excessive door head clearance, at least a portion of component302 may extend beyond the top edge of fire door 102 such that the topedge of component 302 and the door frame 310 immediately above door 102have a gap of no more than ⅛″ as permitted by NFPA 80 for wood and metalfire doors. Component 302 may also help maintain the intumescent seal306 of the L-shaped component 306 in place and protect the head portionof fire door 102 during a fire.

Component 304 may be a stainless steel or steel L-shaped componentwrapping around the push side surface and top edge of door 102 andhaving a vertical portion 312 for mounting to the outer surface of door102 and a horizontal portion 314, which is substantially perpendicularto the vertical portion 312. In accordance with aspects of the presentdisclosure, as shown in FIGS. 10B, 11B, and 13, L-shaped component 304may be selectively positioned on door 102, such that its verticalportion 312 is flush with the push side of door 102 and its horizontalportion 314 is inserted into the door head gap between the top edge ofdoor 102 and the door frame 310 immediately above door 102. Horizontalportion 314, which is generally parallel to the top edge of door 102,may meet the straight component 302 at the pull side of door 102 at thesame height, thereby forming a U-shaped structure covering the headportion of door 102. In the embodiment respectively shown in FIGS. 10Aand 10B, the top side of horizontal portion 314 may be ⅛″ below the doorframe 310 in order to bring fire door 102 into compliance with relevantfire door regulations and codes (e.g., at most ⅛″ as permitted by NFPA80).

L-shaped component 304 may have different widths and lengths (e.g., 36″and 48″) to accommodate fire doors having different widths. In oneembodiment, as shown in FIG. 13, a plurality of through holes may beprovided along a bottom edge of vertical portion 312 (e.g., ⅜″ to thebottom edge), such that L-shaped component 304 may be securely fastenednear the top portion of door 102 and substantially flush with the outersurface of door 102. The number, exact positioning, arrangement andspacing of these through holes may depend upon the dimension of the door102 and desired mechanical strength and stability of component 304.Horizontal portion 314 may be configured to hold or fitted withintumescent strip seal 306 on its top side. Referring to FIG. 10B, theintumescent strip seal 306 may be a 0.65 mm thick self-adhesiveintumescent seal made of TECNOFIRE® 2000 or any suitable fire protectionmaterial. When exposed to high heat of a fire, the intumescent stripseal 306 may expand to fill the opening between the top side ofhorizontal portion 314 and the door frame 310, thereby insulating thehead portion of the door 102 and protecting it from deteriorating andfailing during the fire. It should be appreciated that the specificthickness and/or width of the intumescent seal 306 may be selected inconnection with characteristics of the intumescent materials used suchas expansion ratio, char porosity and thermal conductivity coefficient.The width of horizontal portion 314 may depend on the width of theintumescent strip seal 306 and door 102. Preferably, the horizontalportion 314 is wide enough to hold the intumescent strip seal 306 andspan most of the top edge of door 102.

Furthermore, as shown in FIGS. 10A, 11A, and 14, stainless steel orsteel end caps 308 may be installed on both side ends of door 102 viascrews or any other suitable means. End caps 308 may substantially coverthe opening between horizontal portion 314 and the top edge of door 102,thereby containing the intumescent strip 306 during a fire and allowingit to stay above the door 102. End caps 308 may have a width slightlynarrower than that of the door thickness, such that they do not extendbeyond the edges of door 102 and are easy to install. In one embodiment,as illustrated in FIG. 14, stainless steel end caps 308 may berectangular in shape and have a wall thickness of 0.036″. It should beappreciated that the exact shape, dimensions, and positioning of endcaps 308 may vary depending upon specific configuration and installationof components 302 and 304 on door 102. For example, end caps 308 may beL-shaped wrapping around the narrow end of door 102 with a verticalportion flush with door surface and a horizontal portion under the doorframe.

FIGS. 11A and 11B illustrate a door head system 400 for fire doors withexcessive door head clearances up to ½″, according to aspects of thepresent disclosure. Similar to system 300, system 400 may comprise abrushed stainless steel or steel door cap straight component 302 (asshown in FIG. 12) mounted on a first side (e.g., pull side) of a firedoor 102 that may be a wood or metal fire door, and a brushed stainlesssteel or steel door cap L-shaped component 304 (as shown in FIG. 13)mounted on a second side (e.g., push side) of fire door 102 and fittedwith two intumescent strip seals 316, 318. System 400 may also compriseend caps 308 (as shown in FIG. 14) mounted on both side ends of firedoor 102, and a number of sheet metal screws or any other suitable meansfor fastening all of the above-mentioned component pieces to the headportion of fire door 102. It should be appreciated that the installationof door cap straight component 302 and L-shaped component 304 on pulland/or push sides of fire door 102 may depend upon, amongst otherthings, the specific configuration and dimensions of fire door 102.

In comparison to system 300, system 400 may be implemented to rectify agreater door head clearance up to ½″. In one embodiment, the horizontalportion 314 of L-shaped component 304 may be configured to hold orfitted with intumescent strip seals on its top and bottom sides,respectively. For example, as shown in FIG. 11B, each intumescent stripseal 316, 318 may be a 0.65 mm thick self-adhesive intumescent seal madeof TECNOFIRE® 2000 or any suitable fire protection material. Whenexposed to high heat of a fire, the intumescent strip seals 316, 318 mayexpand to fill the openings between the horizontal portion 314, doorframe 310, and top edge of door 102, thereby insulating the head portionof the door 102 and protecting it from deteriorating and failing duringthe fire. It should be appreciated that the specific thickness and/orwidth of the intumescent seals 316, 318 may be selected in connectionwith characteristics of the intumescent materials used such as expansionratio, char porosity and thermal conductivity coefficient. The width ofhorizontal portion 314 may depend on the width of the intumescent stripseals 316, 318 and door 102. Preferably, the horizontal portion 314 iswide enough to hold the intumescent strip seals 316, 318 and span mostof the top edge of door 102.

It should be appreciated that, although the horizontal portion 314 ofL-shaped component 304 may be fitted with one or two intumescent stripseals described above with respect to FIGS. 10B and 11B, alternativeembodiments of the present disclosure may require no intumescent stripseals to be fitted with the L-shaped component 304.

The above description of the disclosure is provided to enable a personskilled in the art to make or use the disclosure. Various modificationsto the disclosure will be readily apparent to those skilled in the art,and the common principles defined herein may be applied to othervariations without departing from the spirit or scope of the disclosure.Further, the above description in connection with the drawings describesexamples and does not represent the only examples that may beimplemented or that are within the scope of the claims.

Furthermore, although elements of the described aspects and/orembodiments may be described or claimed in the singular, the plural iscontemplated unless limitation to the singular is explicitly stated.Additionally, all or a portion of any aspect and/or embodiment may beutilized with all or a portion of any other aspect and/or embodiment,unless stated otherwise. Thus, the disclosure is not to be limited tothe examples and designs described herein but is to be accorded thewidest scope consistent with the principles and novel features disclosedherein.

1. A system for rectifying excessive bottom clearances of doorassemblies, the system comprising: a door sweep installed on a firstside of a fire door; a door shoe installed on a second opposite side ofthe fire door; an intumescent seal in an opening between a bottom edgeof the fire door and a floor surface; and end caps installed on twonarrow ends of the fire door.
 2. The system of claim 1, wherein thesystem is Underwriters Laboratories Inc. (UL) certified for 90 minutesfire doors.
 3. The system of claim 1, wherein the door sweep comprises asolid neoprene rubber seal fitted with a retaining plate.
 4. The systemof claim 1, further comprising means for securely fastening at least thedoor sweep, door shoe, and end caps to the fire door.
 5. The system ofclaim 1, wherein the intumescent seal is self-adhesive and made ofTECNOFIRE®
 2000. 6. The system of claim 1, wherein the door shoecomprises an L-shaped door shoe having a vertical portion and ahorizontal portion to wrap around the bottom edge of the fire door withan opening between the bottom edge of the fire door and a top side ofhorizontal portion.
 7. The system of claim 6, wherein the intumescentseal is positioned on the top side of the horizontal portion of the doorshoe.
 8. The system of claim 6, wherein each of the end caps covers anopening between the bottom edge of the fire door and the horizontalportion of the door shoe on either narrow side end of the fire door. 9.A system for rectifying excessive bottom clearances of door assemblies,the system comprising: a door sweep installed on either side of a firedoor; an intumescent seal mounted on a bottom edge of the fire door; andend caps installed on two narrow side ends of the fire door.
 10. Thesystem of claim 9, wherein the system is Underwriters Laboratories Inc.(UL) certified for 90 minutes fire doors.
 11. The system of claim 9,wherein the door sweep comprises a solid neoprene rubber seal fittedwith a retaining plate.
 12. The system of claim 9, further comprisingmeans for securely fastening at least the door sweep, door shoe and endcaps to the fire door.
 13. The system of claim 9, wherein theintumescent seal is self-adhesive and made of TECNOFIRE®
 2000. 14. Thesystem of claim 9, wherein each of the end cap covers an opening betweenthe bottom edge of the fire door and a floor surface on either narrowside end of the fire door.
 15. A method for rectifying excessive bottomclearances of door assemblies, the method comprising: providing a doorsweep on a first side of a fire door; mounting a door shoe on a secondopposite side of the fire door; providing an intumescent seal in anopening between a bottom edge of the fire door and a floor surface; andmounting end caps on two narrow ends of the fire door.
 16. The method ofclaim 15, wherein the door sweep comprises a solid neoprene rubber sealfitted with a retaining plate.
 17. The method of claim 15, furthercomprising securely fastening at least the door sweep, door shoe, andend caps to the fire door.
 18. The method of claim 15, wherein theintumescent seal is self-adhesive and made of TECNOFIRE®
 2000. 19. Themethod of claim 15, wherein the door shoe comprises an L-shaped doorshoe having a vertical portion and a horizontal portion to wrap aroundthe bottom edge of the fire door with an opening between the bottom edgeof the fire door and a top side of horizontal portion.
 20. The method ofclaim 19, wherein the intumescent seal is positioned on the top side ofthe horizontal portion of the door shoe.
 21. The method of claim 19,wherein each of the end caps covers an opening between the bottom edgeof the fire door and the horizontal portion of the door shoe on eithernarrow side end of the fire door.
 22. A method for rectifying excessivebottom clearances of door assemblies, the method comprising: providing adoor sweep on either side of a fire door; mounting an intumescent sealon a bottom edge of the fire door; and mounting end caps on two narrowends of the fire door.
 23. The method of claim 22, wherein the doorsweep comprises a solid neoprene rubber seal fitted with a retainingplate.
 24. The method of claim 22, further comprising securely fasteningat least the door sweep, door shoe and end caps to the fire door. 25.The method of claim 22, wherein the intumescent seal is self-adhesiveand made of TECNOFIRE®
 2000. 26. The method of claim 22, wherein each ofthe end cap covers an opening between the bottom edge of the fire doorand a floor surface on either narrow side end of the fire door.